Padlocks are widely used on articles that have obvious or potential security concerns. Referring to FIG. 1, a conventional combination padlock 20 has dialing wheels 22 that may be turned to valid positions to unlatch a movable arm 26 by depressing a movable push button assembly 24.
Some of the padlocks are equipped with dual unlocking modes and enable users to select either way to unlock according to use requirements. Reference can also be found in U.S. Pat. Nos. 4,325,240, 6,539,761, and 6,708,534. These all disclose a padlock that includes key locks that are locked and unlocked by inserting and turning a key and combination locks that are locked and unlocked by setting a combination. The key locks have the advantage of preventing the combination from being decoded, while the combination locks have the convenience of using without a key.
The lock equipped with two locking mechanisms is larger than the lock that has only one lock mechanism. The design of the lock profile also has limitations due to different locations and dimensions of the locking mechanisms.